This invention relates to video display systems and, more particularly, to improvements in the type of video display which employs a deformable layer having deformations that depend upon a stored charge pattern and an optical subsystem for converting the deformations into a viewable image. The subject matter of this application is related to subject matter set forth in copending U.S. patent application Ser. Nos. 679,228 and 679,290, both filed of even date herewith and assigned to the same assignee as the present application.
There have been previously set forth techniques for displaying video information by storing a charge pattern representative of a video frame in a frame store and utilizing the charge pattern to modify a characteristic of a material. The modified characteristic of the material is then used to obtain a viewable image. For example, in U.S. Pat. No. 3,882,271, there is disclosed a system called a solid state light modulator wherein a charge pattern on a special array of semiconductor devices is used to obtain deformations of a conductive reflective layer disposed over the array and spaced therefrom by an elastomer material such as silicone gel. An optical subsystem, such as a Schleiren optical system, can then be utilized to convert the pattern of deformations (or "ripples") in the reflective layer into a viewable image.
There is a unique combination of problems associated with the structure of the semiconductor devices of the described type of solid state light modulator system. A substantial range of voltages must be applied to the individual device electrodes in order to achieve a substantial range of deflection forces on the reflective layer that is separated from these electrodes by a deformable material. For dynamic images, such as in television presentations, the video signals need to be read into the individual deflection electrodes at a fairly high rate. For the device to have good temporal responsiveness, the video-representative signals must be read into the electrodes of the individual semiconductor devices and maintained for a desired period of time at appropriate spacings and amplitudes, all within the constraints of a practical array having a large number of small elements which can be manufactured in quantity at a reasonable cost.
It is among the objects of the present invention to provide a semiconductor array and system which is responsive to this combination of needs, and which exhibits improved overall performance.